There's really no beating around the bushes - just finished the medium door...in sketchup... (original texture was called something mediocre like door2_3...meh, so long interesting names right :P.
I think its futile to try and take the whole original design 100% as it was in the classic doom game, there's no denying that the game was a mishmash of styles thrown in together (the UAC bases never really looked like 'real' space stations or whatever they were). Obviously the tech played a keen role in how the art had to be portrayed (no room on top of another mmmhh!), and with every new doom game there's been (doom 64/Doom 3/Doom II rpg) the art and style has changed.
So i'm trying to stay within the "pay tribute, but not copying 1-1 the designs" ballpark...the door designs are gonna still feel clunky, spacey but also a bit oldschool i'm hoping.